Some American electronic shift transmissions are just slightly modified hydraulic shift units, these can be operated by generating synthetic throttle pressure ( engine load ) , . governor pressure ( road speed ) then letting the rest of the valve body take it from there.

Some have a solenoid to control line pressure and cycle solenoids to command shifts. In these two cases a simple control circuit is enough.

Chrysler in the late 80's was a pioneer in the active electronic shift trans ( the 4 speed front drive 604 ) These trans need a learning sequence to operate properly. They also monitor "fill volumes" to assure proper shift timing as the clutches wear, gain clearance and take longer to apply.